RCD tripping on circuits after new board change nitemare

[Farmelectrics]

Always do eicr on installation before you change board slow down do the tests properly once there ok you can change board in few hours it's easy knowing in advance your board is not going to trip learnt the hard way myself when I was younger lol

 

[vernam616]

Testing before or afterwards dont suppose really matters does it, its still a fault

A better thing when quoting would be to inform the client of the price and then notify them that you have a hourly charge for finding faults on on completion of the new board

Ironically i changed a board this morning, never tested before hand and powered it up, from experience i had already pre determined that they maybe a borrowed neutral from landing light, and there certainly was, so lighting circuits went onto the same mcb, not conventional maybe but not really breaking any rules

 

[micknew]

Testing before or afterwards dont suppose really matters does it, its still a fault

A better thing when quoting would be to inform the client of the price and then notify them that you have a hourly charge for finding faults on on completion of the new board

Ironically i changed a board this morning, never tested before hand and powered it up, from experience i had already pre determined that they maybe a borrowed neutral from landing light, and there certainly was, so lighting circuits went onto the same mcb, not conventional maybe but not really breaking any rules

The only rule it is breaking is that a potentially dangerous situation exists for any electrician working on the circuits who assumes that the wiring was done correctly in the first place.
Seen an electrician thrown off steps due to a borrowed neutral.

 

[vernam616]

Well whats he doing working live then?

The lighting circuits are on the same MCB, so if anyone needs to work on this circuit they should be isolating

I could understand your point if i had put them on seperate mcbs on the same side

 

[telectrix]

even then, you isolate the circuit, then before anything else, check (at the fitting or whatever you are working on) for dead.

 

[micknew]

Still a wiring which was not carried out correctly due to ignorance of the original installer.
You cannot condone borrowed neutrals left on an installation.

 

[vernam616]

Have a little think about what you post before hitting "post reply" button Mick

 

[micknew]

even then, you isolate the circuit, then before anything else, check (at the fitting or whatever you are working on) for dead.

Agree Tel.

 

[micknew]

Have a little think about what you post before hitting "post reply" button Mick

I did.

 

[vernam616]

Nobody said they condoned it, but if the client doesnt want damage or cannot afford to have the circuit altered the alternative is putting them onto the same mcb, yes not conventional but practical and still safely protected by mcb and rcd. Do you understand that if someone isolates that mcb that the neutral wont be live?

 

[vernam616]

Agree Tel.

You have just agreed with him disagreeing with your post of how its potentially dangerous, yet again this forum never ceases to amuse me with some of the comical members

 

[telectrix]

the problem could arise if you had too many lights on the 2 circuits for the 6A MCB. fair enough if wired in 1.5mm, you could uprate the MCB to 10A ( subject to no serious derating issues ), but if circuits are in 1.0mm, then you'd be in the fertilizer

 

[micknew]

Yes I completely agree with you, and take your point that its down to the client whether they want to pay and have it put right.

 

[micknew]

You have just agreed with him disagreeing with your post of how its potentially dangerous, yet again this forum never ceases to amuse me with some of the comical members

Didn't mean to make you laugh, honest.
Just pointing out the bleeding obvious.

 

[vernam616]

Definatley Tel, but elaborated too much on the original theory

The idea of couple the two circuits into one mcb isnt dangerous, unless like you say about derating etc... But then you could argue an "electrician" would know this

 

[vernam616]

Please tell me Mick what was obvious?

Ill tell you whats obvious and if you are an electrician shame on you as its basic stuff

If i couple them two circuits into one mcb and isolate it means no power is going out which means nothing is coming back on the neutral, thats what made me laugh, as its simple theory, if you cant grasp that you shouldnt be working on equipment or trying to tell an electrician that its "potentially dangerous" as the next electrician could get a belt

 

[T&Earth]

Hi I agree, but sometimes you get an old 4 way BS3036 board with NO extra play on cables with CPC & neutrals twisted together and to carry out these test with old board in is virtually impossible.

T&E

Never understood why after a cu change people start having problems due to existing faults, if you aren't prepared to address them then should you really be changing the board in the first place?

 

[ezzzekiel]

Regardless of anything, if you can't trace and fix faults then your in the wrong job.

Sharing an mcb as stated removes the borrowed neutral as it becomes a single circuit, prefer not to see it done this way but sometimes it's the only option

 

[SirKit Breaker]

Its no good clutching at straws.
It is because of things like this that we test the way we do.

Do all the tests, and in the correct order, you will then know if you have a problem with the fixed wiring, and you will be able to identify the reason for the RCD trip, especially if you have a very low IR result, or some interconnection with your circuit.

I will assume that as you have done this job, you are registered or have notified if not, and so you are competent to Inspect and Test, so i dont need to go in depth with these testing procedures, it is all in your GN3 anyway.

Cheers.............Howard

 

[Farmelectrics]

Vernal what would happen if you didn't test before hand and fitted new board and the ir tests were that poor due to old cables that they wouldn't take rcd board rewire would be needed better to no condition of installation before hand